NTN Random Access Preamble Mapping for Doppler-Compatible Uplink
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing random access techniques in non-terrestrial networks (NTN) face challenges due to wide cell coverage and high Doppler shifts, which affect propagation delays and interfere with terrestrial network compatibility.
Innovation Solution
The method involves configuring random access preambles with specific bandwidth and subcarrier spacing relationships, using Zadoff-Chu sequences with different root values, and arranging these sequences in time or frequency domains to maintain compatibility with terrestrial networks while reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a random access procedure designed for terrestrial networks is used in NTN, then compatibility with existing networks is maintained, but the performance is degraded due to large propagation delays, wide cell coverage, and high Doppler shifts
Solution Approach 1:
The patent modifies key parameters of the random access procedure including subcarrier spacing, cyclic prefix length, and preamble sequence properties to accommodate NTN conditions. By changing these parameters, the system maintains compatibility with existing network structures while adapting to the specific challenges of satellite communications such as large propagation delays and Doppler shifts.
Solution Approach 2:
The patent introduces dynamic adjustments to random access parameters based on detected Doppler shift values. The system can adaptively select different preamble formats and adjust timing parameters dynamically, allowing the random access procedure to respond to varying satellite motion conditions while maintaining network compatibility.
2Area of stationary object
If the cell coverage is expanded in NTN, then the service area is increased, but the effects of Doppler shifts and propagation delays are amplified
Solution Approach 1:
The patent applies different random access configurations to different regions within the NTN cell coverage area. By localizing the application of specific preamble formats and parameter sets, the system can optimize performance for terminals experiencing different Doppler shift magnitudes while maintaining overall wide coverage.
3Reliability
If multiple different preamble sequences are generated and transmitted, then the reliability of random access is improved, but the bandwidth occupation and system complexity increase
Solution Approach 1:
The patent segments the random access procedure into multiple attempts with different preamble sequences. Instead of transmitting all sequences simultaneously, the system divides the process into sequential or selectively parallel transmissions, reducing instantaneous bandwidth requirements while maintaining reliability through diversity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for low-complexity random access procedures in NTN environments with wide cell coverage, effectively managing Doppler shifts and maintaining compatibility with terrestrial networks.
Implementation Method 1
effects of Doppler shifts may be large
Implementation Method 2
effects of Doppler shifts may be large
Data Source
AI summary
An operation method of a terminal according to an embodiment of a method and device for random access in a wireless communication system comprises the steps of: receiving random access channel (RACH) configuration information from a base station included in a first network; generating a random access (RA) preamble including a plurality of different preamble sequences on the basis of the RACH configuration information; mapping the RA preamble to a first frequency domain; and transmitting, to the base station, the PA preamble mapped to the first frequency domain, wherein the size of the bandwidth occupied by the first frequency domain and the size of the bandwidth occupied by a physical uplink shared channel (PUSCH) in the first network may be set to have an integer multiple relationship with each other on the basis of the RACH configuration information.